Extraction of botanical material using high-pressure hydrocarbons

ABSTRACT

An apparatus and method for extraction of oils from botanical material using high-pressure hydrocarbons such as propane, or butane, or mixtures thereof are described. A high-pressure propane or butane saturated liquid/vapor mixture formed by pressure reduction through a valve placed before an extraction column, thereby serving as an expansion port was employed. The apparatus is capable of both continuous liquid extraction or batch-style liquid operation through the use of a manifold valve, which directs the solvent liquid/vapor in the system to either a supply tank or an extraction column.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a Divisional application of U.S.Non-Provisional patent application Ser. No. 16/867,431 for “Extractionof Botanical Material Using High-Pressure Hydrocarbons” by ZacharyRichard Lantz, which was filed on May 5, 2020, which claims the benefitof Provisional Patent Application No. 62/843,539 for “Method For HighPressure Hydrocarbon Extraction Of Botanical Material” by ZacharyRichard Lantz, which was filed on May 5, 2019, the entire contents ofboth applications are hereby specifically incorporated by referenceherein for all that they disclose and teach.

BACKGROUND

As the cannabis concentrate market grows, marijuana producers areinvesting in extraction systems since concentrates command a higherprice per item compared to flower (buds) and include a range ofproducts. Hydrocarbon extraction is increasingly used to removecannabinoids, terpenes, flavonoids, and other active cannabis compoundsfrom the hemp or cannabis plants, and compared with other popularextraction solvents such as ethanol and carbon dioxide (CO2),hydrocarbons (propane and butane) offer increased product quality anddiversity.

Hydrocarbons are naturally-occurring compounds made up of hydrogen andcarbon atoms and, of these, butane and propane are the most commonlyused hydrocarbons for closed-loop extractions. Both are considered“light hydrocarbons” due to their low molecular weight, and a singlesolvent or a blend of propane and butane may be employed to produceunique consistencies and different ratios of cannabinoids from the plantmaterial.

Butane is a non-polar solvent with a boiling point of 31.1° F., whichenables lower temperatures to be used in purging the solvent withoutdegrading volatile terpene compounds. Propane has a boiling point of−43.6° F., which makes it better for extracting some terpenes.

During the extraction run, hydrocarbon solvent is flushed over the plantmatter into the material column. As the butane, propane, or blendedmixture washes over the organic plant matter, the solvent is capable ofdissolving cannabinoids, terpenes, flavonoids, phenolic amides, andsterols to create a full-spectrum extract. After the dissolutionprocess, the solvent is separated from the solution and the oil iscollected for further processing. The refined concentrate is stored in acollection vessel, the solvent removed by heating the vessel, andcaptured in a solvent storage tank for re-use. Closed-loop systemsensure the majority of the solvent is reclaimed.

SUMMARY

In accordance with the purposes of the present invention, as embodiedand broadly described herein, an embodimentof the apparatus forextraction of oils from botanical material using a hydrocarbon solventhaving a chosen pressure and a selected temperature, hereof, includes:an extraction column having a first closed end, a second closed end, andan interior volume, for containing the botanical material; a first valvein fluid communication with the volume and disposed at the first end ofthe extraction column for receiving the hydrocarbon solvent, the firstvalve being adjustable such that the chosen pressure of the hydrocarbonsolvent is reduced and the selected temperature of the hydrocarbonsolvent is reduced by expansion of the hydrocarbon solvent through thefirst valve, forming thereby a saturated liquid-vapor mixture of thehydrocarbon solvent; a second valve in fluid communication with thevolume and disposed at the second end of the extraction column forreceiving the saturated liquid-vapor mixture of the hydrocarbon solventafter the saturated liquid-vapor mixture of said hydrocarbon solvent haspassed through the botanical material, forming thereby a saturatedliquid-vapor mixture of the hydrocarbon solvent containing extractedbotanical material; an extraction basin in fluid communication with thesecond valve for receiving the saturated liquid-vapor mixture of thehydrocarbon solvent containing extracted botanical material; a heaterfor providing heat to the extraction basin in order to boil off thehydrocarbon solvent from the saturated liquid-vapor mixture of thehydrocarbon solvent containing extracted botanical material, leavingextracted oils from the botanical material in the extraction basin; arecovery pump for compressing the hydrocarbon solvent after thehydrocarbon solvent is boiled off from the extraction basin; a thirdvalve in fluid communication with the extraction basin and in fluidcommunication with the recovery pump; a condenser for cooling thecompressed hydrocarbon solvent; a hydrocarbon solvent storage tank; anda manifold valve for directing the cooled, compressed hydrocarbonsolvent into the first valve or the hydrocarbon solvent storage tank.

In another aspect of the present invention and in accordance with itspurposes, as embodied and broadly described herein, an embodiment of themethod for extraction of oils from botanical material using ahydrocarbon solvent having a pressure and a temperature, hereof,includes: reducing the pressure and cooling the hydrocarbon solvent suchthat a saturated liquid-vapor mixture thereof is formed; contacting thebotanical material with a saturated liquid-vapor mixture of thehydrocarbon solvent forming thereby a saturated liquid-vapor mixture ofthe hydrocarbon solvent containing extracted botanical material; boilingoff the hydrocarbon solvent from the saturated liquid-vapor mixture ofthe hydrocarbon solvent containing extracted botanical material, leavingextracted oils from the botanical material; compressing the boiled offhydrocarbon solvent; cooling the compressed hydrocarbon solvent; anddirecting the cooled, compressed hydrocarbon solvent to a hydrocarbonstorage tank therefor, or reducing the pressure and cooling the cooled,compressed hydrocarbon solvent such that a saturated liquid-vapormixture thereof is formed.

Benefits and advantages of the present invention include, but are notlimited to, providing an apparatus and method for extraction of oilsfrom botanical material using high-pressure hydrocarbons such aspropane, or butane, or mixtures thereof, whereby solvent channeling iseliminated, impurity content in final product is minimized, efficiencyof extraction of the solvents is increased, and no liquid nitrogen isrequired for fresh frozen plant extraction.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and form a part ofthe specification, illustrate the embodiments of the present inventionand, together with the description, serve to explain the principles ofthe invention. In the drawings:

FIG. 1 is a is a phase diagram for butane illustrating pressure in baraas a function of temperature in degrees centigrade.

FIG. 2 is a phase diagram for propane illustrating pressure in bara as afunction of temperature in degrees centigrade.

FIG. 3A is a schematic representation of an embodiment of the apparatusfor high-pressure hydrocarbon extraction of botanic materials, whileFIG. 3B is a chart of the vapor pressures for propane and butane as afunction of temperature between 100% propane and 100% butane andmixtures thereof.

DETAILED DESCRIPTION OF THE INVENTION

Briefly, embodiments of the present invention include an apparatus andmethod for extraction of oils (including cannabinoids, terpenes,flavonoids, phenolic amides, and sterols, as examples) from botanicalmaterial using high-pressure hydrocarbons such as propane, or butane, ormixtures thereof. A high-pressure propane or butane saturatedliquid/vapor mixture formed by pressure reduction through a valve placedbefore an extraction column, thereby serving as an expansion port wasemployed. A pressure drop From 100 psi to 80 psi was found to convertabout 20 psi from liquid to vapor, and absorb sufficient heat from itsenvironment to cool the remaining 80 psi upon injection.

The apparatus is capable of both continuous liquid extraction orbatch-style liquid operation through the use of a manifold valve, whichdirects the solvent liquid/vapor in the system to either a supply tankor an extraction column. The present invention also allows phasetransition control of the hot discharge vapor from a recovery pump,which enables injection liquid/vapor temperature control for continuousoperation.

Current methods for extracting oil from oil-bearing plants includepassing a liquid solvent through the botanical material initially undervacuum such that air is removed, then collecting the product-ladensolvent in a collection basin to which heat is applied in order toremove the solvent from the product for recovery by boiling. Externalheat may be applied to the extraction column using a heating jacket topurge remaining solvent from the botanical material into the recoverysystem. Both passive operation (using hot water and ice) to performphase transitions or active operation (using a recovery pump torecompress the gas into phase transition) are typical modes of operationfor the previous art.

One difficulty involved with previous methods is known as “SolventChanneling”, a condition in which the solvent forms tight channelswithin the product column that result in poor extraction of the productaway from the channel of solvent. Another problem for passive operationis the need to fill and move cumbersome and heavy solvent tanks.Additional heating and cooling capacity are also required to transferfluids from tank to tank. Further, passive operation is much slower thanactive operation due to wait times for thermodynamic equilibrium. Forcold liquid solvent injection used to enable cold liquid solventinjection into the extraction column, chilling the supply tank can causeany water in the system to turn into ice which can block the supply tubeand clog the system. Cold extraction typically helps to keep fats,waxes, lipids, and other non-desirable materials behind and within theplant material.

The present invention can be better understood by likening it to arefrigeration system that has been redesigned into an extraction systemas a result of several modifications. An injection valve replaces theexpansion valve of the refrigeration system, and a removable botanicalmaterial extraction column with a recovery basin for removing theextracted product from the solvent, before returning to the compressor,valve, both to be described in more detail below, replacing theevaporator coil of the refrigeration system. R290 Propane, R600 Butane,and R600a Isobutane are all refrigerants commonly used in refrigerationsystems that are also standard hydrocarbon extraction solvents found inthe botanical material extraction industry, and some food processingindustries.

As the refrigeration cycle predicts, the quality of the gas at theexpansion valve consists on average of between 75% to 88% liquid. Unlessthe biomass is being chilled by an external jacket, then it will likelybe at room temperature (25 C). When compared to 50 psi propane (−10 C)the biomass would serve instead as a source of heat and boil off moresolvent. The addition of a condenser can liquify all the vapor producinga subcooled liquid that can be compressed above the expectedtemperature/pressure relationship seen with a gas/liquid mixture or apure vapor. Once in this state, the compressed subcooled liquid can bedirected to all spaces within the column to where atomization is notnecessary. For the liquid/vapor mixture of the present invention (notsubcooled liquid), compression above 120 psi forces a phase changebetween gas and liquid as more molecules are compressed much closertogether condense within the biomass in hard-to-reach spaces such as theupper corners, thus eliminating the need for atomization.

Embodiments of the present invention permit operation of a botanicalextraction apparatus at a higher pressure, while maintaining a lowextraction temperature by utilizing the subcooling effect from acondenser, if needed, and can also exploit an injection valve acting asan expansion valve to further reduce the injecting solvent temperatureby boiling a small portion of liquid to absorb heat from the remainingliquid, thereby and cool it by auto-refrigeration. As a liquid-vapormixture the present solvent takes on properties that would otherwise notbe experienced in an extraction using a pure liquid.

First, once above 120 psi, anywhere there is pressure there is solvent,which eliminates solvent channeling since the liquid takes the path ofleast resistance as it flows to the bottom of an extraction column.

Second, being a mixture of liquid and vapor, the solvent takes on afog-like state which has smaller solvent molecules performing theextraction process, instead of large groups as seen with a large volumeliquid. The solvent then has lower holding capacity due to lowerphysical surface area per molecule, whereby the solvent saturates withthe most soluble products first; that is, short chainmolecules/non-polar molecules, such as terpenes and cannabinoids, beforeabsorbing the larger chain molecules such as fats and waxes. Thisminimizes impurity content in final product.

Third, once cannabinoids are liquefied by the solvent, the cyclingaction of the compressor moving solvent through the extraction column ata moderate speed and pressure, physically extracts the liquid molecules,thereby increasing the efficiency of extraction of the present solvents.

Additionally, sub-cooled solvent, by itself, is typically less capableof carrying a solute than a warm solvent and therefore more solvent willbe needed to perform the same extraction while producing an overallpurer product. Cold solvent is also required for fresh frozen plantextraction in order to keep the biomass frozen during the extractionprocess, in order to prevent impurities from entering the solventstream. Traditionally this was performed with liquid nitrogen injection,thereby creating a new problem in that the nitrogen must be separatedfrom the solvent before compressing the solvent into the tank in orderto prevent overpressure issues. The need for nitrogen is eliminated inembodiments of the present apparatus by subcooling the solvent in thecondenser and by additional auto-refrigeration at theinjection/expansion valve of the extraction column.

Reference will now be made in detail to the present embodiments of theinvention, examples of which are illustrated in the accompanyingdrawings. In the Figures, similar structure will be identified usingidentical reference characters. It will be understood that the FIGURESare presented for the purpose of describing particular embodiments ofthe invention and are not intended to limit the invention thereto.Turning to FIGS. 1 and 2 , illustrated are phase diagrams for butane andpropane, respectively, illustrating pressure in bara as a function oftemperature in degrees centigrade. Additional data (nitrogen injectionrange) can be applied to both phase diagrams. This zone can be achievedwithout using nitrogen as in traditional processing, by subcooling theextraction solvent prior to injection while creating a high-pressurezone with the extraction drain valve mostly closed. Low-pressure liquidversus a high-pressure cycle are indicated on these diagrams as roomtemperature and pre-chilled liquid, without additional head pressure.

FIG. 3A is a schematic representation of an embodiment of apparatus, 10,for high-pressure hydrocarbon extraction of botanic materials, whileFIG. 3B is a chart of the vapor pressures for propane and butane as afunction of temperature between 100% propane and 100% butane andmixtures thereof. These values are used when determining the currentmixture ratio and to determine if there is atmosphere pressure in thesupply tank. It can also be used to obtain an approximate butane phasediagram based on the propane phase diagram, because they are verysimilar gases, and their enthalpy and entropy values will approximatelyfollow the same drop as seen in the chart. Such analysis is only validfor saturated liquid-vapor mixture or for pure vapor, as the pure liquidmay be compressed and give incorrect values.

Turning to FIG. 3A, liquid propane gas (LPG) solvent, 12, followinggeneral flow direction, 14, is directed into extraction column, 16,through valve, 18, which is adjusted to provide a pressure drop, asmeasured between pressure gauges, 20 and 22. Solvent 12 is therebycooled a few degrees as it enters extraction column 16. Valve, 24,controls the ability to soak or to pressurize extraction column 16 abovethat of extraction basin, 26, as measured by pressure gauge, 28. Once inextraction basin 26, heat from heater, 30, is applied to boil LPG 12,now containing extracted botanic material from extraction column 16.Valve, 32, is adjusted so that there is a pressure difference betweenextraction basin 26 pressure gauge 28 and pressure gauge, 34, for oilseparator, 36, of at least 10 psi, preferably greater than 25 psi, andmost preferably greater than 50 psi. The pressure drop forces extractedproduct to remain in extraction basin 26 while the propane or butanegas, 38, continues into oil separator 36. From here, the gas iscompressed, 40, by recovery pump, 42, to a pressure measured by pressuregauge, 44, and sent into variable temperature condenser, 46, having itstemperature controlled by chiller, 48. This allows LPG, 50, temperaturereturning through manifold valve, 52, to be maintained withoutexperiencing over-heating. If LPG 50 becomes too hot, it must bere-compressed into supply tank, 54, and fresh liquid withdrawn. Thetemperature of supply tank 54 is controlled by heater/chiller, 56.Inline condenser 46 following recovery pump 42 permits the control ofthe maximum temperature of the returning gas so as to stay within therequired extraction pressure window. From condenser 46, LPG 50 returnsto control manifold valve 52 where its direction, 58, can either be intosupply tank 54 or 12 to the extraction system as a high-pressuresolvent.

For use with propane, a pump inlet pressure greater than 15 psi,preferably greater than 25 psi, and most preferably within the range of30-50 psi inlet pressure to pump 42. This provides a sufficiently highgas density for extraction with a solvent quality in the range between40% and 80% liquid at expansion valve 18. Typical pump outlet pressuresrange between 50 psi and 150 psi for extraction, and between 150 psi and250 psi for high-pressure cycle condenser bypass. With butane, a pumpinlet pressure greater than 5 psi, preferably greater than 10 psi andmost preferably within the range between 16 and 25 psi inlet pressure,with typical pump outlet pressures ranging between 15 psi and 65 psi forextraction, and between 65 psi and 120 psi for high-pressure cyclecondenser bypass.

A pump inlet pressure of or less than 10 psi, more preferably 5 psi, andmost preferably between 0 and 2 psi pump inlet pressure performsoppositely, and forces the exhaust solvent to become too hot to returnto its liquid state without removing a large amount of heat, which isachieved by bypassing heat exchanger 46. Once heat exchanger 46 isbypassed, all heat generated by pump 42 is added to the solvent vapor,and carried by the vapor into extraction column 16 to boil off remainingsolvent trapped in the biomass.

Temperature zones A, B, C, and D in FIG. 3A are controlled by adjustingthe pressure ratios on both sides of manifold valve 52, valve 18, valve24, and valve 32, with 0 to 20+ psi between pressure gauge 44 (higher)and pressure gauge 20, 0 to 30+ psi pressure difference between pressuregauge 20 (higher) and pressure gauge 22, and 50+ psi pressure differencebetween pressure gauge 34 (lower) and pressure gauge 28.

As pressure increases, solubility decreases, while at the same time, astemperature increases solubility increases. With gaseous solvents,increase of pressure typically results in an increase in temperature,just as a decrease in pressure results in a decrease in temperature.Just as an increase in pressure will increase the density, to an extent,which also alters solubility, a decrease in pressure reduces the amountof solvent molecules which makes the solvent no longer capable ofcarrying an extracted product due to density loss. This is relative inthat as pressure/temperature increases, the quality of the liquid alsochanges from approximately 85% liquid to lower than 15% liquid. Only asub-cooled liquid can experience an increase in pressure without anincrease in temperature. Due to this a window in which the gas remainsat a liquid quality viable for extraction has been found under specificconditions.

As temperature increases, solubility will also increase. This isexperienced at approximately 220 psi in that the curve takes on anexponential rate compared to previous state. At this point the gas willwant to become more vapor than liquid, but also the temperature increasechanges from about (1 deg/psi) to (5-10 deg/psi). At this point moreimpurities will start to be extracted as the solvent density decreasesdue to increased temperature. At pressures under 220 psi, the solventdoes not gain more heat than pressure and instead remains closer to 1:1,while remaining more liquid than vapor. Thus, low-pressure vapor-liquidwill have higher liquid density due to quality when it is at a lowerpressure than at a higher pressure with the correct pressure at thecompressor, and there be a higher percentage of liquid available forsolvation at lower pressure—until below a specific temperature wheresolvent solubility becomes important and specific products will nolonger be soluble.

These known physical attributes of gaseous solvent extraction, within aspecific window, are used to generate a saturated liquid-vapor mixture,which is neither gas or liquid, but contains both at the same time. Theliquid-to-gas ratio can be controlled by maintaining a specific range ofpressure/temperature during extraction, whereby traditional problemssuch as solvent channeling and low yields are eliminated.

Traditional methods of extraction utilize pure liquid from the supplytank with no vapor present, nor is there a return of vapor/liquid fromthe compressor to the extraction system without first returning to thesupply tank. In accordance with the teachings of embodiments of thepresent invention, the apparatus removes the need for a supply tankduring the extraction process, and the need for a large volume ofsolvent to be stored on site. That is, in the present process, the hotgas from the compressor, perhaps slightly cooled in the condenser, isdirected into the extraction column without going through the supplytank. This allows the use of the heat generated from the process toreturn to the column as a hot vapor (no liquid due to low compressorinlet pressure and bypassing the condenser and supply tank) which thenboils the remaining thermally locked-out solvent from the extractioncolumn. This process is much more rapid than using a heater and can beperformed with non-jacketed columns. Once the column reaches the desiredtemperature, then full recovery can be performed after which theextraction column is purged using the compressor and the condenser andthe solvent is then returned to the supply tank.

Ordinarily, a solvent to biomass ratio of between 1:5 and 1:10 isdesired. With usual extraction apparatus, this would require the abilityto have on site up to 1500 lbs. of solvent in the extraction room(1:10). However, by using the present apparatus, the extraction processcan be performed with about 50 lbs. of solvent on average within thesystem. It takes about 2 min. to pass 60 lbs. of solvent through thecolumn. As for solvent channeling, once the pressure is above 120 psiand below 220 psi the solvent density within extraction column 16 iswithin the window to which any space at this pressure will be also at aliquid state.

High-pressure hydrocarbon extraction enables one to extract a higheryield per unit of solvent with a lower impurity content due to modifiedsolvent properties. The high-pressure environment enables the mostsoluble product to rapidly saturate the solvent, while the least solubleproducts remain in the biomass material. However, the flow solvent mayextract some undesirable products while the solvent cycles across thebiomass. Extracted cannabinoid content is typically between 50% and 75%of the total cannabinoids. This range reflects cannabinoid ratio of theinput material, a low cannabinoid content can cause final product toalso have a lower overall cannabinoid content. High cannabinoid contentcrude enables the production of previously impossible to make productssuch as Cannabidiol-Acid (CBD-a), which is known to be the highestanti-inflammatory of all cannabinoids.

During high-pressure hydrocarbon extraction, continuous solventextraction is being performed on the product loaded into extractioncolumn 16. Solvent 12 is not returned to supply tank 54 from recoverypump 42, but instead first sent to a variable temperature condenser 46,then into vapor control manifold 52, to which then returns to extractioncolumn 16 through valve 18—depressurization point. Variable temperaturecondenser 46 is set to a point so that the exhaust gas is at apre-determined pressure as desired for the extraction. This allows forcontinuous, non-stop high-pressure hydrocarbon extraction of the productat a set temperature/pressure relationship. With a bypass system ormanifold to allow gas to cycle without entering extraction column 16,the system does not need to recover the gas until the end of theprocessing day. Only adding solvent to the system throughout the day dueto losses will be necessary to maintain operating conditions.

Heating extraction column 16 during the extraction cycle and/or at theend of the final cycle, using heater/chiller, 58, increases the finalrecovery rate which increases extraction efficiency. The presentapparatus permits the condenser to be bypassed, thereby allowing all theheat generated by the low inlet pressure to the compressor, whichcompresses the solvent to a high outlet pressure, thus adding heat tothe solvent as it is compressed in relation to the amount ofdifferential it is being compressed. This then forces the remainingliquid in the extraction columns to be vaporized, at which point is mucheasier to recover with the compressor than as a liquid that is thermallylocked out (too cold to boil at current conditions). That is, the heatgenerated by the compressor becomes the source of heat to boil remainingsolvent in the extraction columns, once the condenser is bypassed. Theprocess of solvent recovery expends the most time during the extractionprocess. Latent solvent in the product loaded into extraction column 16can become “locked-up” within the system due to boiling under vacuumuntil below its boiling point. Column heat addition accelerates theremoval of this latent solvent and minimizes recovery times.

As seen with the Phase diagrams in FIGS. 1 and 2 , simple adjustments tothe pressure/temperature relationship will force the solvent totransition between gaseous or liquid state. With this knowledge andValves 18, 24, and 32, the injection temperature and liquid/gas ratiocan be controlled by adjusting each valve to produce the requiredpressure differential between zones. Thus, the injection valve(expansion valve) is used as a thermal controller based on expansion ofgas from the supply manifold to the extraction column to the basin tothe compressor. Various zones require adjustment of valving during theextraction process due to environment changes—such as when the basinpressure increases, the flow into the compressor will need to beadjusted to maintain set input.

At the end of the day or at the end of the extraction cycle, the solventgas may be recovered into supply tank 54 by means of control manifold52. Supply tank 54 may be placed in ice water, 60, or be jacketed orhave an internal cooling coil controlled by heater/chiller 56 to aid inthe condensation of the solvent and speed the recovery cycle. However,the only time the supply tank needs to be operationally connected to theextraction system is during the initial solvent injection—at thebeginning of the day, and sequentially topped off as needed throughoutthe day to maintain solvent density within the system.

The foregoing description of the invention has been presented forpurposes of illustration and description and is not intended to beexhaustive or to limit the invention to the precise form disclosed, andobviously many modifications and variations are possible in light of theabove teaching. The embodiments were chosen and described in order tobest explain the principles of the invention and its practicalapplication to thereby enable others skilled in the art to best utilizethe invention in various embodiments and with various modifications asare suited to the particular use contemplated. It is intended that thescope of the invention be defined by the claims appended hereto.

What is claimed is:
 1. A method for extraction of oils from botanicalmaterial using a hydrocarbon solvent having a pressure and atemperature, comprising: reducing the pressure and cooling saidhydrocarbon solvent such that a saturated liquid-vapor mixture thereofis formed; contacting said botanical material with a saturatedliquid-vapor mixture of said hydrocarbon solvent forming thereby asaturated liquid-vapor mixture of said hydrocarbon solvent containingextracted botanical material; boiling off said hydrocarbon solvent fromsaid saturated liquid-vapor mixture of said hydrocarbon solventcontaining extracted botanical material, leaving extracted oils fromsaid botanical material; compressing said boiled off hydrocarbonsolvent; cooling said compressed hydrocarbon solvent; and directing saidcooled, compressed hydrocarbon solvent to a hydrocarbon solvent storagetank therefor, or reducing the pressure and cooling said cooled,compressed hydrocarbon solvent such that a saturated liquid-vapormixture thereof is formed.
 2. The method of claim 1, wherein saidhydrocarbon solvent is chosen from propane, butane and mixtures thereof.3. The method of claim 1, further comprising the step of removingextracted botanical material from said hydrocarbon solvent, before saidstep of compressing said boiled off hydrocarbon solvent.
 4. The methodof claim 2, wherein for propane said step of compressing said boiled offhydrocarbon solvent changes the pressure of said boiled off hydrocarbonsolvent from between 15 psi and 50 psi to between 50 psi and 150 psi. 5.The method of claim 4, wherein for propane said hydrocarbon solventcomprises between 40% and 80% liquid propane after said step of reducingthe pressure and cooling said hydrocarbon solvent.
 6. The method ofclaim 1, wherein continuous extraction of oils from botanical materialoccurs after reducing the pressure and cooling said cooled, compressedhydrocarbon solvent such that a saturated liquid-vapor mixture thereofis formed.
 7. The method of claim 1, wherein said oils comprisecannabinoids, terpenes, flavonoids, phenolic amides, and sterols.